comparison layer/SpectrogramLayer.cpp @ 1028:78ece8cdfaee spectrogram-minor-refactor

Start repainting from the middle -- but this is quite unreliable

 
                     cache.validArea =
                         QRect(px, cache.validArea.y(),
                               pw, cache.validArea.height());
 
+                    if (cache.validArea.width() == 0) {
+                        recreateWholeImageCache = true;
+                    }
+                    
 #ifdef DEBUG_SPECTROGRAM_REPAINT
                     cerr << "SpectrogramLayer: valid area now "
                               << px << "," << cache.validArea.y()
                               << " " << pw << "x" << cache.validArea.height()
                               << endl;

             cache.validArea = QRect();
 	}
     }
 
     if (recreateWholeImageCache) {
-        x0 = 0;
+        if (!m_synchronous) {
+            // When rendering the whole thing, start from somewhere near
+            // the middle so that the region of interest appears first
+            x0 = int(v->getPaintWidth() * 0.4);
+        } else {
+            x0 = 0;
+        }
         x1 = v->getPaintWidth();
     }
 
     // We always paint the full height when refreshing the cache.
     // Smaller heights can be used when painting direct from cache

         cachePainter.end();
     }
 
     // update cache valid area based on painted area
         
-    int left = min(cache.validArea.x(), x0);
-
-    if (cache.validArea.width() == 0) {
-        left = 0; // cache was not valid at all
-    }
-
-    int wid = max(cache.validArea.x() + cache.validArea.width() - left,
-                  x1 - left);
-
+    int left = x0;
+    int wid = x1 - x0;
+    
     if (failedToRepaint > 0) {
 #ifdef DEBUG_SPECTROGRAM_REPAINT
         cerr << "SpectrogramLayer: Reduced painted extent from "
              << left << "," << wid;
 #endif

 #ifdef DEBUG_SPECTROGRAM_REPAINT
         cerr << " to " << left << "," << wid << endl;
 #endif
     }
     
+    if (cache.validArea.width() > 0) {
+        left = min(left, cache.validArea.x());
+        wid = cache.validArea.width() + wid;
+    }
+
     cache.validArea = QRect(left, 0, wid, h);
 
 #ifdef DEBUG_SPECTROGRAM_REPAINT
     cerr << "SpectrogramLayer: Cache valid area becomes " << cache.validArea.x()
          << ", " << cache.validArea.y() << ", "